Hard disk drives are information storage devices that use thin film magnetic media to store data. Referring to FIG. 1a, a typical hard disk drive 1 in prior art comprises a head stack assembly (HSA) 10 with slider 11 (shown in FIG. 1b) thereon, a magnetic disk 12 mounted on a spindle motor 13 which causes the magnetic disk 12 to spin, and a motor base 14 to enclose the above-mentioned components.
The slider 11 flies over the surface of the magnetic disk 12 at a high velocity to read data from or write data to concentric data tracks on the magnetic disk 12, which is positioned radially by a voice coil 15 embedded (e.g. by epoxy potting or overmolding) in a fantail spacer 16 of the HSA 10. Generally, a voice coil motor (VCM) 16 is used to drive the voice coil 15.
Referring to FIG. 1b, a traditional HSA 10 includes an actuator coil assembly (ACA) 101, a fantail spacer 16 interposed in the ACA 101 via the voice coil 15, at least an HGA 102 connected with the ACA 101, and a controlling circuit 140 for controlling the HGA 102. The ACA 101 has at least one top surface 131 for mounting the HGA 102, and a side surface 132 for mounting the control circuit 140.
As shown in FIG. 1b, the controlling circuit 140 is a flexible printed circuit assembly (FPCA) that includes a printed circuit board assembly (PCBA) 141 for connecting with a preamplifier (not shown) and a flexible printed circuitry (FPC) 142 connecting with the PCBA 141. And the FPC 142 electrically connects to the HGA 102, and mounts on the side surface 132 of the ACA 101.
The HGA 102 includes a suspension 190 and a slider 11 supported by the suspension 190, and the suspension 190 includes a flexure 126 having a head 126a and a tail 126b, and the flexure 126 runs from the slider 11 to the tail 126b. The tail 126 is bent for connecting with the FPC 142. The tail 126 has several bonding pads 128 formed thereon. Concretely, the FPC 142 includes several bonding pads 143 formed thereon. The HGA 102 is connected with the FPC 142 by connected the bonding pads 128 with the bonding pads 143 via several solder balls (not shown).
Additionally, the assembly of the disk drive unit 1 further includes solder connections between the slider 11 and the suspension 190, the FPC 142 and the fantail spacer 16, for example.
The following is descriptions of a conventional apparatus for forming solder connection between two pre-welding surfaces in the disk drive unit 1.
As shown in FIG. 2, the conventional soldering apparatus 180 commonly includes a nozzle device 181, a solder ball feeding device 182, a laser generator 183 and a gas feeding device 184. The nozzle device 181 has a main passage 185 which is tapered. A solder ball 186 is supplied from a first passage 187 connected with the solder ball feeding device 182 and the nozzle device 181, and then the nitrogen gases are supplied from a second passage 188 so as to prompt the solder ball 186 to move to the outlet 191, and finally the laser beams are emitted from a third passage 189 so as to melt the solder ball 186 and reflow to the pre-welding surfaces 150.
In this state, the nitrogen gases and the laser beams are hard to control. For example, it's hard to control the timing of supplying laser beams, and it's also hard to control the energy of the laser beams and the quantity of nitrogen gases. Therefore, the laser energy and the pressure in the nozzle device 181 are unstable, which may affect the soldering result. Furthermore, as the solder ball, the nitrogen gases and the laser beams are provided to the nozzle device 181 from three different passages, and the three passages and the main passage 185 are integrative and unitary, thus it's quite inconvenient to clean or change the nozzle device 181, which may spend a lot of time and workload.
Thus, there is a need for an improved apparatus and method for forming electrical solder connections in a disk drive unit to overcome the drawbacks mentioned above.